Implantable medical devices are devices adapted for implantation within the body for treatment of one or more disorders of a patient. Common implantable medical devices include pacemakers, implantable cardioverter defibrillators (ICDs), spinal cord stimulation (SCS) systems, deep brain stimulation (DBS) systems, and peripheral nerve stimulation systems.
These types of implantable systems generally include a pulse generator and one or more leads. A stimulation lead includes a lead body of insulative material that encloses wire conductors. The distal end of the stimulation lead includes multiple electrodes that are electrically coupled to the wire conductors. The proximal end of the lead body includes multiple terminals, which are also electrically coupled to the wire conductors, that are adapted to receive electrical pulses. The distal end of a respective stimulation lead is implanted adjacent or within tissue to be stimulated to deliver the electrical pulses to the appropriate tissue associated with the patient's disorder(s). The stimulation leads are then tunneled to another location within the patient's body to be electrically connected with a pulse generator or, alternatively, to an “extension.”
The pulse generator is typically implanted within a subcutaneous pocket created during the implantation procedure. In many implant systems, the subcutaneous pocket is disposed in a lower back region, although subclavicular implantations and lower abdominal implantations are commonly employed for various types of therapies.
The pulse generator is typically implemented using a metallic housing that encloses circuitry for generating the electrical pulses, control circuitry, communication circuitry, a battery, etc. The pulse generating circuitry is coupled to one or more stimulation leads through electrical connections provided in a “header” of the pulse generator. Specifically, feedthrough wires typically exit the metallic housing and enter into a header structure of a moldable material. Within the header structure, the feedthrough wires are electrically coupled to annular electrical connectors. The header structure holds the annular connectors in a fixed arrangement that corresponds to the arrangement of terminals on a stimulation lead.